This invention is related to descrambling a transport stream. In particular, this invention is related to descrambling a transport stream using information from a smart card.
The National Renewal Security System (NRSS) has defined two types of conditional access (CA) modules, an NRSS-A module (with a smart card form factor) and NRSS-B module (with a PCMCIA form factor). Not only are the form factors different for the part A and part B modules but also the protocols are different.
A television (TV), set top box, or cable box manufacturer may need to provide two types of NRSS slots for the CA module, one that has a smart card form factor, and one that has a PCMCIA form factor, and support the protocols for each. To support the two conditional access modules, a TV, set top box or cable box manufacturer currently needs to implement a separate NRSS-B PCMCIA form factor reader as well as a separate NRSS-A smart card form factor reader, as shown in FIGS. 1 and 2.
FIG. 1 shows an NRSS-B CA module 100 that receives smart card 110. A smart card interface 120 transmits signals from the smart card 110 to central processing unit (CPU) 130. The CPU 130 detects control words from the signals, and sends the control words to descrambler integrated circuit (IC) 140. The descrambler IC 140 receives a scrambled transport stream from host 150, descrambles the stream using the control words, and outputs a descrambled stream to copy protection module 160. Copy protection module 160 protects the descrambled stream and transmits the stream back to host 150. The copy protected descrambled stream may be a digitally formatted movie, for example.
FIG. 2 shows an NRSS-A smart card 200 that receives a scrambled transport stream from host device 210. The scrambled stream is received by descrambler IC 220. CPU 230 sends control words to descrambler IC. The descrambler IC 220 then uses the control words to descramble the transport stream and to output a descrambled stream to host 210. The stream is protected by copy protection module 240, and the descrambled copy protected transport stream is set from smart card 200 to host 210.
An adapter having a slot, a connector, and a passive router that routes signals from a smart card inserted in the slot to the connector, is disclosed.